Question

我有以下代码：

    public List<OversizeElement> GetOversizeRegulations(List<string> states)
    {
        var tmpList = (from i in _db.States
                       where states.Any(p=>i.Name == p)
                       select new
                       {
                           StateID = i.ID,
                           StateName = i.Name,
                           StateShortName = i.ShortName
                       }).ToList();

所以，我为“状态”中的所有州选择了其他信息。变量。它有效，但我需要获得相同的顺序，就像在＆＃39;状态＆＃39;变量。怎么排序呢？它需要IComparer对象，但我无法想象如何在我的情况下编写它

Answer 1

如果您想要原始订购，可以执行以下操作：

public List<Destination> GetOversizeRegulations(List<string> states)
{

        var tmpDictionary = (from i in _db.States
                             where states.Contains(i.Name)
                             select new
                                      {
                                        StateID = i.Id,
                                        StateName = i.Name,
                                        StateShortName = i.ShartName
                                      }
                              ).ToDictionary(k => k.StateName, k => k);

        var result = states
                    .Where(m=>tmpDictionary.ContainsKey(m))
                    .Select(m => tmpDictionary[m]).ToList();


 }

Answer 2

枚举states而不是_db.States：

var tmpList = states
              .Select(s => _db.States.SingleOrDefault(st => st.Name == s))
              .Where(s => s != null)
              .Select(new
              {
                  StateID = s.ID,
                  StateName = s.Name,
                  StateShortName = s.ShortName
              });

Answer 3

您可以在IndexOf功能中使用OrderBy功能。假设您在两个列表中都有相同的id字段。让我们在这个例子中说id被称为StateId：

var tmpList = (from i in _db.States
                   where states.Any(p=>i.Name == p)
                   select new
                   {
                       StateID = i.ID,
                       StateName = i.Name,
                       StateShortName = i.ShortName
                   }).OrderBy(s => states.Select(x => x.StateId).IndexOf(s.StateId)).ToList();

LINQ to Entities - 按数组排序

3 个答案: